The Colne Valley Viaduct is a railway bridge that will carry High Speed 2 over the Colne Valley Regional Park and the Grand Union Canal. It runs between Harefield in Hillingdon, Greater London and Denham in Buckinghamshire. At a length of 3.38 km and a weight of 116,000 tonnes, it is the longest railway bridge in the UK. It is one of the largest single civil engineering works of HS2 Phase 1. From Wikipedia
